Image forming and plate making method and apparatus

ABSTRACT

An image forming apparatus comprises: an image forming body comprising a substrate and a self-assembling compound adsorbed to a surface of the substrate to form a self-assembling monomolecular film; a first desorbing device for selectively desorbing at least a part of the self-assembling compound forming the self-assembling monomolecular film from the surface of the image forming body, so as to provide the surface of the image forming body with a desorbed face and an undesorbed face which have wettabilities different from each other; a developing device for supplying the surface of the image forming body with ink which preferentially attaches to one of the desorbed face or undesorbed face; and a transfer device for transferring to a recording medium the ink attached to the surface of the image forming body. In this apparatus, a printing plate can easily be formed and erased, and the same printing plate can be used repeatedly. Therefore, higher-speed printing, smaller dimensions in the apparatus, lower running cost at the time of copy-printing a small number of sheets can be realized, while making it possible to achieve higher resolution.

TECHNICAL FIELD

The present invention relates to an image forming apparatus, an imageforming method, and a platemaking method. More specifically, the presentinvention relates to an image forming apparatus, an image formingmethod, and a platemaking method, which are characterized in their imageforming body used as a printing plate.

BACKGROUND ART

Known as conventional printers are electrophotographic printers,mimeograph printers, and the like.

In the electrophotographic printer, the whole surface of a clean drum iselectrically charged by corona discharge, and the electrically chargeddrum surface is selectively exposed to light. The exposed surface isdischarged, whereby a latent image can be formed on the drum surface bya charged area and an uncharged area. After the latent image is formed,toner is attached to the drum surface by a developing section, so as toform a visual image. Thus formed visual image is transferred onto arecording medium in a transfer section, and then is fixated to therecording medium by a fixating section.

Since the electrophotographic printer necessitates a process of forminga latent image per sheet at the time of printing a plurality of sheets,however, there is a limit to increasing the printing speed.

In the mimeograph printer, which is known as a light-duty printer forbusiness use, on the other hand, a thermal head selectively forms holesin a stencil, so as to form a printing plate. Thus formed plate is woundabout a drum, and then ink is supplied to the plate from the inside ofthe drum, whereby an ink image is formed by the ink passed through theabove-mentioned holes. Thereafter, the ink image is transferred to arecording medium in a transfer section.

The mimeograph printer, however, has the following drawbacks. Namely,the plate wound about the drum has to be discarded after the printing isover. As a consequence, it is necessary to provide a mechanism forremoving the plate to be discarded from the drum, a space for storingthus removed plate carrying ink, and a complicated mechanism for takingthe plate out of the apparatus. Since ink attaches to the plate to bediscarded, the amount of use of ink unnecessarily increases, therebyraising the cost of prints. Further, since no new image can be formed ona mimeograph stencil which has once been prepared, a new mimeographstencil is necessary for forming a new plate. Thus, it isdisadvantageous in that, while the running cost per sheet at the time ofcopy-printing a large number of sheets becomes lower, the running costper sheet at the time of copy-printing a small number of sheets becomeshigher. Also, since processes of discarding the used stencil, forming anew plate, winding the plate about a drum, and so forth are necessaryfor printing a new image, it is disadvantageous in that the apparatuscomplicates its structure and enhances its dimensions.

DISCLOSURE OF THE INVENTION

In view of the above-mentioned problems inherent in the prior art, it isan object of the present invention to provide a novel image formingapparatus and image forming method in which a printing plate can easilybe formed and erased, and the same printing plate can be usedrepeatedly, thereby making it possible to reduce the dimensions of theapparatus, lower the running cost at the time of copy-printing a smallnumber of sheets, and realize a higher resolution; and a method ofmaking such a printing plate for image formation.

As a result of diligent studies for achieving the above-mentionedobject, the inventors have found that the object can be attained when aprinting plate is formed by using, as an image forming body, a substratecovered with a film (i.e., self-assembling monomolecular film) formed bya material (i.e., self-assembling compound) which is detachably adsorbedto the surface of the substrate and is substantially regularly arrangeddue to intermolecular mutual actions, and then selectively desorbing atleast a part of the self-assembling compound forming the self-assemblingmonomolecular film; thereby accomplishing the present invention.

Namely, the image forming apparatus in accordance with the presentinvention comprises:

an image forming body comprising a substrate and a self-assemblingcompound adsorbed to a surface of the substrate to form aself-assembling monomolecular film;

a first desorbing device for selectively desorbing at least a part ofthe self-assembling compound forming the self-assembling monomolecularfilm from the surface of the image forming body, so as to provide thesurface of the image forming body with a desorbed face and an undesorbedface which have wettabilities different from each other;

a developing device for supplying the surface of the image forming bodywith ink which preferentially attaches to one of the desorbed face orundesorbed face; and

a transfer device for transferring to a recording medium the inkattached to the surface of the image forming body.

The image forming apparatus in accordance with the present invention mayfurther comprise a first film forming device which supplies the surfaceof the substrate with the self-assembling compound and forms theself-assembling monomolecular film on the surface of the substrate.

The image forming apparatus in accordance with the present invention mayfurther comprise a second film forming device which supplies the surfaceof the image forming body with the self-assembling compound and formsthe self-assembling monomolecular film on the desorbed face again. Inthis case, it is preferred that the image forming apparatus furthercomprise a second desorbing device which desorbs the self-assemblingcompound forming the undesorbed surface from the surface of the imageforming body, so as to cause the whole surface of the image forming bodyto become the desorbed face.

The image forming apparatus in accordance with the present invention mayfurther comprise a moisture supply device which supplies, before the inkis supplied, moisture which preferentially attaches to one of thedesorbed face or undesorbed face, to the surface of the image formingbody.

Preferable as the desorbing device in the image forming apparatus inaccordance with the present invention is a heating device which appliesthermal energy to the self-assembling compound forming theself-assembling monomolecular film, so as to desorb the compound.

The image forming method in accordance with the present invention is amethod including:

a first desorbing step of selectively desorbing, from a surface of animage forming body comprising a substrate and a self-assembling compoundadsorbed to a surface of the substrate to form a self-assembling film,at least a part of the self-assembling compound forming theself-assembling monomolecular film, so as to provide the surface of theimage forming body with a desorbed face and an undesorbed face whichhave wettabilities different from each other;

a developing step of supplying the surface of the image forming bodywith ink which preferentially attaches to one of the desorbed face orundesorbed face; and

a transfer step of transferring to a recording medium the ink attachedto the surface of the image forming body.

The image forming method in accordance with the present invention mayfurther comprise a first film forming step of supplying the surface ofthe substrate with the self-assembling compound and forming theself-assembling monomolecular film on the surface of the substrate.

The image forming method in accordance with the present invention mayfurther comprise a second film forming step of supplying the surface ofthe image forming body with the self-assembling compound and forming theself-assembling monomolecular film on the desorbed face again. In thiscase, it is preferred that the image forming method further comprise asecond desorbing step of desorbing the self-assembling compound formingthe undesorbed surface from the surface of the image forming body, so asto cause the whole surface of the image forming body to become thedesorbed face.

The image forming method in accordance with the present invention mayfurther comprise a moisture supply step of supplying, before the ink issupplied, moisture which preferentially attaches to one of the desorbedface or undesorbed face, to the surface of the image forming body.

Preferable as the desorbing step in the image forming method inaccordance with the present invention is a heating step of applyingthermal energy to the self-assembling compound forming theself-assembling monomolecular film, so as to desorb the compound.

The platemaking method in accordance with the present invention is amethod including:

a desorbing step of selectively desorbing, from a surface of an imageforming body comprising a substrate and a self-assembling compoundadsorbed to a surface of the substrate to form a self-assembling film,at least a part of the self-assembling compound forming theself-assembling monomolecular film, so as to provide the surface of theimage forming body with a desorbed face and an undesorbed face whichhave wettabilities different from each other, thereby yielding aprinting plate.

The platemaking method in accordance with the present invention mayfurther comprise a film forming step of supplying the surface of thesubstrate with the self-assembling compound and forming theself-assembling monomolecular film on the surface of the substrate.

Preferable as th e desorbing step in the platemaking method inaccordance with the present invention is a heating step of applyingthermal energy to the self-assembling compound forming theself-assembling monomolecular film, so as to desorb the compound.

The above-mentioned self-assembling compound in the present inventionis, as will be described later in detail, a compound which canspontaneously form a substantially uniform adsorption film of amonomolecular layer (self-assembling monomolecular film) on apredetermined substrate surface (solid-liquid interface). A preferableexample thereof is one having an adsorptive functional group which canbe adsorbed to the surface of the substrate and an aliphatic compoundresidue combined to the adsorptive functional group.

Also, at least two kinds of self-assembling compounds may be used in thepresent invention, whereby an adsorption film of a monomolecular layerhaving a minute uneven structure is spontaneously formed on the surfaceof the substrate. As such at least two kinds of self-assemblingcompounds, preferable are those having their respective aliphaticcompound residues with main chain lengths different from each other andwettabilities identical to each other, and those having their respectivealiphatic compound residues with steric configurations different fromeach other and wettabilities identical to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart showing a preferred embodiment of the imageforming method and platemaking method in accordance with the presentinvention;

FIGS. 2A to 2F are schematic views in section showing states of asubstrate surface at various steps in a preferred embodiment of theimage forming method in accordance with the present invention,respectively;

FIGS. 3A and 3B are schematic views in section each showing an exampleof the state of a desorbed face formed in the image forming body inaccordance with the present invention;

FIG. 4 is a schematic view in section showing an example of the state inwhich a self-assembling monomolecular film is re-formed in the imageforming body in accordance with the present invention;

FIGS. 5A to 5F are schematic views in section showing states of thesubstrate surface in various steps of another preferred embodiment ofthe image forming method in accordance with the present invention,respectively;

FIGS. 6A and 6B are schematic views in section showing other examples ofthe state of the desorbed face formed in the image forming body inaccordance with the present invention, respectively;

FIG. 7 is a schematic view in section showing another example of thestate in which a self-assembling monomolecular film is re-formed in theimage forming body in accordance with the present invention;

FIG. 8 is a schematic view in section showing another example of thestate in which a self-assembling monomolecular film has been formed inthe image forming body in accordance with the present invention;

FIG. 9 is a schematic view showing a preferred embodiment of the imageforming apparatus in accordance with the present invention;

FIG. 10 is a schematic view in section showing an example of the statein which a self-assembling compound in accordance with the presentinvention is adsorbed to a substrate surface;

FIG. 11 is a schematic view in section showing an example of the statein which the self-assembling compound in accordance with the presentinvention is selectively desorbed from the substrate surface;

FIG. 12 is a schematic view in section showing an example of the statein which the self-assembling compound in accordance with the presentinvention is adsorbed to the substrate surface again;

FIG. 13 is a schematic view showing another preferred embodiment of theimage forming apparatus in accordance with the present invention;

FIG. 14 is a schematic view in section showing another example of thestate in which the self-assembling compound in accordance with thepresent invention is adsorbed to the substrate surface;

FIG. 15 is a schematic view in section showing another example of thestate in which the self-assembling compound in accordance with thepresent invention is selectively desorbed from the substrate surface;

FIG. 16 is a schematic view in section showing an example of the statein which the self-assembling compound in accordance with the presentinvention is adsorbed to the substrate surface again;

FIG. 17 is a schematic view showing still another preferred embodimentof the image forming apparatus in accordance with the present invention;

FIG. 18 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is adsorbed to the substrate surface;

FIG. 19 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is selectively desorbed from the substrate surface;

FIG. 20 is a schematic view showing still another preferred embodimentof the image forming apparatus in accordance with the present invention;

FIG. 21 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is adsorbed to the substrate surface;

FIG. 22 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is selectively desorbed from the substrate surface;

FIG. 23 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is desorbed from the whole substrate surface;

FIG. 24 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is adsorbed to the substrate surface; and

FIG. 25 is a schematic view in section showing still another example ofthe state in which the self-assembling compound in accordance with thepresent invention is selectively desorbed from the substrate surface.

BEST MODES FOR CARRYING OUT THE INVENTION

In the following, preferred embodiments of the present invention will beexplained in detail with reference to the drawings. Among the drawings,parts identical or equivalent to each other will be referred to withnumerals or letters identical to each other.

First, the self-assembling monomolecular film in accordance with thepresent invention will be explained.

When adsorbed (chemically adsorbed) to a specific substrate surface, aso-called self-assembling compound is arranged substantially regularlyon the substrate surface due to the molecular assembling property of theformer (the adsorption action due to the adsorptive functional group andthe intermolecular mutual actions caused by the groups combined to theadsorptive functional group). Films formed by such an arrangement arereferred to as self-assembling monomolecular films or self-assembledmonolayers (abbreviated as SAM). Also, thus regularly arranging theself-assembling compound on the substrate surface is referred to asmodifying the substrate surface with the self-assembling compound. Aphenomenon such as that mentioned above is reported in R. G. Nuzzo etal., J. Am. Chem. Soc., 105 (1983), 4481-4483 (*0), and the like, fromwhich the above-mentioned phenomenon has been known to occur betweenspecific materials (a substrate and a self-assembling compound).

Though not restricted in particular, examples of the substrate inaccordance with the present invention include metals such as gold,platinum, silver, copper, aluminum, and the like; oxides such asaluminum oxide, silicon oxide, and the like; resins such as polyethyleneand the like; selenides such as zinc selenide and the like; and asingle-crystal silicon. Among these, the metals such as gold, platinumand the like, and the oxides such as aluminum oxide, silicon oxide andthe like are preferable; and gold and platinum are particularlypreferable.

Though not restricted in particular, examples of the self-assemblingcompound in accordance with the present invention include the following.Here, *1 to *8 in the following explanation indicate the referencesdisclosing their corresponding self-assembling compounds.

(I) A thiol compound expressed by general formula (1): HSR¹, which isrepresented by:

i) absorptive functional group: SH group (thiol group);

ii) substrate: gold, silver, or the like; and

iii) R¹: aliphatic compound residue, which is more specifically selectedfrom the following:

a) alkyl residue (e.g., —(CH₂)_(m)CH₃ where m=1 to 21, *1, 2, 3, 4, 5,6);

b) halogen (F, Br, Cl)-substituted alkyl residue (e.g.,—(CH₂)₂(CF₂)_(n)CF₃ where n=5 to 15, —(CH₂)_(o)CF₃ where o=5 to 15,—(CH₂)₁₁Br, —(CH₂)₁₁C, *1, 2);

c) alkenyl residue (e.g., —(CH₂)₁₇CH═CH₂, *1);

d) alcohol residue (e.g., —(CH₂)_(p)OH where p=2 to 22, *1, 2, 4, 6);

e) aliphatic carboxylic acid residue (e.g., —(CH₂)_(q)COOH where q=1 to15, *1, 2, 6);

f) aliphatic carboxylic acid ester residue (e.g., —(CH₂)_(r)COOCH₃ wherer=10 to 15, *1, 6);

g) aliphatic ether residue (e.g., —(CH₂)₁₁OCH₃, *1 );

h) aliphatic thiol ester residue (e.g., —(CH₂)₁₂SCOCH₃, *1);

i) alkyl cyanide residue (e.g., —(CH₂)₈CN, *1);

j) siloxylated alkyl residue (e.g., —(CH₂)₁₁OSi(CH₃)₂(C(CH₃)₃), *1); and

k) carbamoyl alkyl residue (e.g., —(CH₂)₁₅CONH₂, *6).

(II) A disulfide compound expressed by general formula (2): R²SSR³,which is represented by:

i) adsorptive functional group: SS group (disulfide group);

ii) substrate: gold or the like;

iii) R²and R³ being either identical or different from each other, eachbeing an aliphatic compound residue, which is more specifically selectedfrom the following:

a) alkyl residue (e.g., —(CH₂)_(s)CH₃ where s=0 to 17, *7);

b) halogen (F, Br, Cl)-substituted alkyl residue;

C) alkenyl residue (e.g., —(CH₂)₂₀CH═CH₂, *7);

d) alcohol residue (e.g., —(CH₂)_(y)OH where y=2 to 22);

e) aliphatic carboxylic acid residue (e.g., —(CH₂)_(t)COOH where t=2 to10, *7);

f) aliphatic amine residue (e.g., —(CH₂)₂NH₂, *7); and

g) R² and R³ forming a group expressed by the following generalexpression:

[where R²¹ and R³¹ may be either identical or different from each other,each indicating H—, CF₃(CF₂)_(u)CO— where u=0 to 6, CF₃(CF₂)_(v)CO—where v=0 to 14, or (p—NO₂)C₆H₄CO—] (*7).

(III) A sulfide compound expressed by general formula (3): R⁴SR⁵, whichis represented by:

i) adsorptive functional group: S group (sulfide group);

ii) substrate: gold or the like;

iii) R⁴ and R⁵ being either identical or different from each other, eachbeing an aliphatic compound residue, which is more specifically selectedfrom the following:

a) alkyl residue (e.g., —(CH₂)₁₇CH₃, *1); and

b) halogen (F, Br, Cl)-substituted alkyl residue.

(IV) A carboxylic acid compound expressed by general formula (4):HOOCR⁶, which is represented by:

i) adsorptive functional group: COOH group (carboxylic group);

ii) substrate: platinum, aluminum, zinc selenide, polyethylene, or thelike;

iii) R⁶ being an aliphatic compound residue, which is more specificallyselected from the following:

a) alkyl residue (e.g., —C_(w)H_(2w+1) where w=4 to 19, cyclopentylgroup, *1, 6); and

b) halogen (F, Br, Cl)-substituted alkyl residue (e.g., —(CF₂)₁₀CF₃,*1).

(V) An amine compound expressed by general formula (5): H₂NR⁷, which isrepresented by:

i) adsorptive functional group: NH₂ group (amino group);

ii) substrate: platinum, polyethylene, or the like;

iii) R⁷ being an aliphatic compound residue, which is more specificallyselected from the following:

a) alkyl residue (e.g., —(CH₂)₁₇CH₃, *1); and

b) halogen (F, Br, Cl)-substituted alkyl residue.

(VI) A diazo compound expressed by general formula (6): N₂R⁸, which isrepresented by:

i) adsorptive functional group: N₂ group (diazo group);

ii) substrate: aluminum oxide, silicon oxide, or the like;

iii) R⁸ being an aliphatic compound residue, which is more specificallyselected from the following:

a) aliphatic ketone residue (e.g., —CHCO(CH₂)_(x)CH₃ where x=14 to 16,*8).

(VII) An azide compound expressed by general formula (7): N₃R⁹, which isrepresented by:

i) adsorptive functional group: N₃ group (azide group);

ii) substrate: aluminum oxide, silicon oxide, or the like;

iii) R⁹ being an aliphatic compound residue, which is more specificallyselected from the following:

a) aliphatic carboxylic acid residue (e.g., —OCO(CH₂)₁₅CH₃, *8); and

b) aliphatic aldehyde residue (e.g., —CO(CH₂)₁₆CH₃, *8).

(VIII) Others

A silicon compound (e.g., CH₃(CH₂)₁₇SiCl₃, *1), which is represented by:

i) adsorptive functional group: Si (silicon); and

ii) substrate: silicon.

An aldehyde (e.g., HCONH(CH₂)₄CH₃, HCONHCH(CH₂CH₃)₂, HCONHC₅H₉,HCONHC(CH₃)₃, *6), which is represented by:

i) adsorptive functional group: CO (carbonyl group); and

ii) substrate: polyethylene.

(References)

1: C. D. Bain et al., J. Am. Chem. Soc., 111 (1989), 321-335.

2: M. D. Porter et al., J. Am. Chem. Soc., 114 (1992), 5860-5862.

3: M. D. Porter et al., J. Am. Chem. Soc., 109 (1987), 3559-3568.

4: G. H. Whitesides et al., Langmuir, 8 (1992), 1330-1341.

5: M. D. Porter et al., J. Electro. Chem., 310 (1990), 335-359.

6: Minoru Inoue, Adhesion and Adhesives, Vol. 34, No. 7 (1990), 289-292.

7: R. G. Nuzzo et al., J. Am. Chem. Soc., 109 (1987), 2358-2368.

8: D. A. Holden et al., Tetrahedron, 43 (1987), 1671-1678.

Here, without being restricted to those mentioned above, theself-assembling compound in accordance with the present invention may beany compound as long as it can form a self-assembling monomolecular filmon a predetermined substrate surface. Since sulfur exhibits a specificaffinity for gold, however, the above-mentioned thiol compound,disulfide compound, and sulfide compound including sulfur as anabsorptive functional group are preferable when gold is used as asubstrate.

Also, without being restricted to those mentioned above, the aliphaticcompound residue constituting the self-assembling compound in accordancewith the present invention is selected depending on the combination ofthe substrate and adsorptive functional group employed and the like.When an alkyl residue or a halogen-substituted aliphatic compoundresidue (e.g., halogen-substituted alkyl residue) or an alcohol residueis used as the aliphatic compound residue, the one having a carbonnumber within the range of 1 to 22 is preferable, and the one having acarbon number within the range of 5 to 15 is particularly preferable. Itis due to the fact that the thermal stability of the bonding between thesubstrate and self-assembling compound tends to become too high when thecarbon number is too large, whereas there tends to occur a possibilitythat the self-assembling compound adsorbed to the substrate fails toattain a sufficient uniformity when the carbon number is too small.

The self-assembling monomolecular film formed by the above-mentionedself-assembling compound yields a surface in which the terminal ofaliphatic compound residue (which is the end on the side not combined tothe adsorptive functional group) is substantially uniformly arranged,whereby the wettability of the monomolecular surface is not influencedby the substrate surface. As a consequence, controlling the terminalfunctional group on the self-assembling monomolecular film surface (theterminal functional group of the aliphatic compound residue) enables thesurface to have various characteristics. Namely, using awater-repellent, oil-repellent, or water- and oil-repellent functionalgroup as its terminal functional group together with a substrate havinga surface with a wettability (e.g., hydrophilic and lipophilicproperties) different from that of the terminal functional group cancontrol the wettability of the image forming body surface constitutedthereby, so as to be utilized in the image forming apparatus.

For example, when a self-assembling compound having at a terminal analkyl residue in which only hydrogen atoms are combined to its carbonmain chain is self-assembled to a hydrophilic and lipophilic substratesurface, then the surface of the monomolecular film exhibitswater-repellent and lipophilic properties. As a consequence, the areamodified with the self-assembling compound becomes water-repellent,whereas the unmodified area becomes hydrophilic. On the other hand, whena self-assembling compound having at a terminal an alkyl residue whosehydrogen atoms have partly or completely been substituted by a halogen(fluorine or the like) is self-assembled to a hydrophilic and lipophilicsubstrate surface, then the surface of the monomolecular film exhibitswater- and oil-repellent properties. As a consequence, the area modifiedwith the self-assembling compound becomes water- and oil-repellent,whereas the unmodified area becomes hydrophilic and lipophilic.

Also, in the present invention, a mixture of at least two kinds ofmaterials may be used as the above-mentioned self-assembling compound.As they are adsorbed to the substrate surface while mingling with eachother, a self-assembling monomolecular film having a minute (micro)uneven structure is formed on the surface.

As a minute uneven structure is formed on the surface of theself-assembling monomolecular film, its surface area increases, therebyemphasizing the direction of wettability of the surface. Namely, thewater- or oil-repellent property in the surface having a minute unevenstructure becomes greater than that in a flat surface when the surfaceof the self-assembling monomolecular film is water- or oil-repellent,whereas the hydrophilic or lipophilic property in the surface having aminute uneven structure becomes greater than that in the flat surfacewhen the surface of the self-assembling monomolecular film ishydrophilic or lipophilic. As a consequence, in a surface covered with aself-assembling monomolecular film having a minute uneven structureformed thereon, the oil-repellent property with respect to oil ink orthe water-repellent property with respect to water ink or moisturebecomes greater, thereby sufficiently preventing minute droplets fromremaining. Here, though the dimensions of the minute uneven structureare not restricted in particular, H/L is preferably 0.1 or greater,where L is the diameter of a depression (diameter of a protrusion) and His the depth of the depression (height of the protrusion). It is due tothe fact that the direction of wettability is less likely to beemphasized if the ratio in the minute uneven structure is less than theabove-mentioned value.

At least two kinds of self-assembling compounds which can be used in thepresent invention are not restricted in particular in terms of theircombination as long as they can form a self-assembling monomolecularfilm having the above-mentioned minute uneven structure. Examples ofpreferable combinations include (i) a combination of at least two kindsof self-assembling compounds having respective adsorptive functionalgroups which can be adsorbed to the surface of the substrate, andrespective aliphatic compound residues with main chain lengths differentfrom each other and wettabilities identical to each other; and/or (ii) acombination of at least two kinds of self-assembling compounds havingrespective adsorptive functional groups which can be adsorbed to thesurface of the substrate, and respective aliphatic compound residueswith steric configurations different from each other and wettabilitiesidentical to each other.

In the case of the combination (i), the difference in the number ofcarbon atoms constituting the respective main chains of the differentkinds of aliphatic compound residues is preferably about 3 to 10. Theminute uneven structure is less likely to be formed when theabove-mentioned carbon number difference is not greater than 2; whereaslonger chains tend to fall upon shorter chains when the above-mentionedcarbon number difference is 11 or greater, thereby making it less likelyto form minute unevenness.

In the case of the combination (ii), on the other hand, it will bepreferable if the combination of aliphatic compound residues havingsteric configurations different from each other comprises an aliphaticcompound residue of a straight chain structure and an aliphatic compoundresidue of a structure having a side chain (e.g., an alkyl group orhalogen-substituted alkyl group having a carbon number of 1 to 3), sincea minute (molecular-level) uneven structure tends to be formed reliablythereby. Preferably, the above-mentioned side chain exists in thevicinity of the terminal of the aliphatic compound residue (on the sidenot combined to the adsorptive functional group).

Further, it is not necessary for at least two kinds of self-assemblingcompounds (aliphatic compound residues) in accordance with the presentinvention to have wettabilities completely identical to each other. Itwill be sufficient if at least one of water- or oil-repellent propertyis common.

In the self-assembling monomolecular film having a minute unevenstructure formed by the above-mentioned at least two kinds ofself-assembling compounds, minute droplets are sufficiently preventedfrom remaining in the surface as mentioned above. Consequently, whenthis film is utilized in the image forming apparatus, there occurs atendency to sufficiently prevent prints from getting soiled due to theremaining ink, and whitening from occurring in the prints and theprinting density from becoming unstable due to the remaining moisture.Namely, in the case where the desorbed face and the surface modifiedwith the self-assembling compound are used as an image area and anon-image area, respectively, ink is sufficiently prevented fromadhering to the non-image area, whereby prints with less soil can beobtained. When the surface modified with the self-assembling compoundand the desorbed face are used as the image area and the non-image area(the desorbed face being provided with a dampening solution), thenmoisture is sufficiently prevented from diffusing into the image area,whereby prints having less whitening, fading, and the like caused by theremaining moisture can be obtained.

With reference to FIGS. 1 and 2A to 2F, preferred embodiments of theimage forming method and platemaking method in accordance with thepresent invention will now be explained in detail. FIG. 1 is a flowchartshowing a preferred embodiment of the image forming method in accordancewith the present invention (steps S101 to S103 corresponding to apreferred embodiment of the platemaking method in accordance with thepresent invention), whereas FIGS. 2A to 2F are schematic views insection showing respective states of a substrate surface at varioussteps in a preferred embodiment of the image forming method inaccordance with the present invention (FIGS. 2A and 2B corresponding torespective states of the substrate surface at various steps in apreferred embodiment of the platemaking method in accordance with thepresent invention).

First, in this embodiment, a surface of a substrate 1 is immersed in asolution 3 of a self-assembling compound 2, so as to supply theself-assembling compound 2 to the surface of the substrate 1.Consequently, as shown in FIG. 2A, the self-assembling compound 2 issubstantially uniformly arranged and adsorbed to the surface(solid-liquid interface) of the substrate 1 in a spontaneous manner, soas to form an adsorption film of a monomolecular layer (self-assemblingmonomolecular film), thereby yielding an image forming body 4 (firstfilm forming step S101). The self-assembling compound 2 is constitutedby an adsorptive functional group 2 a and an aliphatic compound residue2 b combined to the adsorptive functional group 2 a. As shown in FIG.2B, the adsorptive functional group 2 a is adsorbed to the surface ofthe substrate 1, whereas the terminal of the aliphatic compound residue2 b is exposed to the surface of the self-assembling monomolecular film(the face on the exposed side).

The factors influencing the forming speed of such a self-assemblingmonomolecular film include temperature, the kind of solvent, theconcentration of solution, and the like. They are appropriatelyselected, according to the combination of the self-assembling compoundand substrate used, so as to increase the forming speed. Here, themonomolecular film can be formed at room temperature as well. Though thesolvent is not restricted in particular, its intrusiveness into themonomolecular layer is preferably low, and organic solvents arepreferred from the viewpoint of the solubility of the self-assemblingcompound. Among these, ethanol (protonic polar solvent), ethyl acetate(nonprotonic polar solvent), hexane (nonpolar solvent), and the like arepreferably used. For reliably obtaining a monomolecular film, theconcentration of solution is preferably 0.0001 mM or higher,particularly preferably at least 0.01 mM but not higher than 10 mM. Itis due to the fact that it tends to take a longer time for forming amonomolecular film if the concentration of solution is too low, whereasthere is a tendency of the self-assembling compound itself inhibitingthe self-assembling or the excess self-assembling compound beingdeposited on the surface if the concentration of solution is too high.Here, it is not always necessary for the self-assembling monomolecularfilm to be formed onto the substrate surface to such an extent that themonomolecular film is completely formed (the compound density attains asaturated state). It will be sufficient if the self-assembling compoundis substantially uniformly adsorbed to the substrate surface so that thewettability of the monomolecular film surface differs from thewettability of the substrate surface. Hence, even in the case where ittakes several minutes to several hours for obtaining a completemonomolecular film, an image forming body in which differentwettabilities are caused by a substantially uniform monomolecular filmcan be obtained in several seconds (see *1).

Subsequently, the self-assembling monomolecular film formed in the imageforming body 4 is washed with a solvent, so as to eliminate the part ofself-assembling compound not involved in film formation, and then isdried so as to eliminate the solvent (washing/drying step S102). Such awashing step is not always necessary, and the drying step may be carriedout alone.

Then, as shown in FIG. 2B, thermal energy 6 is selectively applied froma first thermal head 5 to the self-assembling compound 2 forming theself-assembling monomolecular film, so as to selectively desorb theself-assembling compound 2 from the surface of the image forming body 4.Consequently obtained is the image forming body 4 (i.e., a printingplate for image formation (transfer)) whose surface is formed with adesorbed face 7 and an undesorbed face 8 which have wettabilitiesdifferent from each other (first desorbing step S103).

The temperature and time used for desorbing such a self-assemblingmonomolecular film are appropriately selected according to thecombination between the self-assembling compound and substrate (thermalstability of the monomolecular film) used, and the temperature ispreferably within the range of 100 to 300° C. After the first desorbingstep S103, a step of eliminating the desorbed self-assembling compound 2by washing the surface of the image forming body 4 and then eliminatingthe washing liquid by drying (not depicted) may further be provided.

In the desorption of the self-assembling compound 2, the self-assemblingcompound 2 to be desorbed is not needed to be desorbed completely fromthe substrate 1. It will be sufficient if, as shown in FIG. 3A, at leastthe aliphatic compound residue 2 b is desorbed (so as to leave theadsorptive functional group 2 a alone), whereby the wettability of thedesorbed face 7 and that of the undesorbed face 8 differ from eachother. Also, as shown in FIG. 3B, a part of the self-assembling compound2 on the desorbed face 7 may completely be desorbed, while only thealiphatic compound residue 2 b may be desorbed in the remainingself-assembling compound 2. It is due to the fact that, depending on thecombination of the self-assembling compound and substrate used, thereare cases where the desorption of the self-assembling compound 2 fromthe substrate 1 is preferentially carried out, where the desorption(decomposition) of the aliphatic compound residue 2 b from theself-assembling composition 2 is preferentially carried out, and wherethe adsorptive functional group 2 a is desorbed from the substrate 1after the aliphatic compound residue 2 b is desorbed (decomposed) fromthe self-assembling compound 2 (see *9: Masahiko Hara et al., Journal ofApplied Physics, Japan, Vol. 64, No. 12 (1995), 1234-1238).

Subsequently, moisture (which may contain additives and the like) 10 issupplied to the surface of the image forming body 4 from a moisturesupply device 9 (moisture supply step S104). FIG. 2C shows a case wherethe desorbed face 7 is hydrophilic and lipophilic, whereas theundesorbed face 8 is water-repellent and lipophilic, whereby themoisture 10 preferentially adheres to the desorbed face 7.

Thereafter, ink (oil ink) 12 is supplied to the surface of the imageforming body 4 from a developing device 11 (developing step S105). Asshown in FIG. 2D, the ink 12 preferentially adheres to the lipophilicundesorbed face 8, while bypassing the desorbed face 7 provided with themoisture 10 attached thereto, thereby forming an ink image.

Then, as shown in FIG. 2E, a recording medium 13 abuts against the imageforming body 4, whereby the ink 12 attached to the surface of the imageforming body 4 is transferred to the recording medium 13 (transfer stepS106). Hence, the first printing sequence (printing process) iscompleted.

If a plurality of sheets of the same image are to be copy-printedsubsequently (S108: “No”), the untransferred ink 12 attached to thesurface of the image forming body 4 is eliminated (untransferred inkeliminating step S107), and then the moisture supply step S104,developing step S105, transfer step S106, and untransferred inkeliminating step S107 are repeated a predetermined times as indicated byA in FIG. 1. Here, it is not always necessary to carry out theuntransferred ink elimination and moisture supply each time.

Thus, in the image forming method of the present invention, the sameprinting plate can be used repeatedly. Consequently, in accordance withthe present invention, it is not necessary to form a latent image persheet as required in the conventional electrophotographic printer,whereby high-speed printing is possible.

After the copy printing of a desired number of sheets is completed(S108: “Yes”), thermal energies 15 are applied to the self-assemblingcompound 2 forming the undesorbed face 8 from second thermal heads 14 asshown in FIG. 2F, so as to desorb the self-assembling compound 2 fromthe surface of the image forming body 4. As a consequence, the wholesurface of the image forming body 4 becomes a desorbed face (seconddesorbing step S109). Thereafter, as indicated by B in FIG. 1, theself-assembling compound 2 is supplied to the surface of the imageforming body 4 again, whereby the self-assembling monomolecular film isformed on the above-mentioned desorbed face again (second film formingstep S101). Then, as the above-mentioned various steps (S101 to S109)are repeated, a desired number of sheets are copy-printed for each of aplurality of images.

Here, in the case where the above-mentioned second desorbing processingS109 is carried out, the uniformity of the re-formed self-assemblingmonomolecular film tends to improve. However, since the self-assemblingcompound 2 tends to be adsorbed to the desorbed face 7 alone, as shownin FIG. 4, so as to re-form the monomolecular film in this part (see*9), the second desorbing step S109 is not always necessary.

Thus, in the image forming method of the present invention, the sameimage forming body can repeatedly be used for a plurality of images, andthe forming and erasing of the printing plate is possible by simpleprocessing operations of immersion to a solution and heating. Therefore,in accordance with the present invention, complicated devices fordiscarding stencils and winding new stencils, which have beennecessitated in the conventional mimeograph printer, are unnecessary,whereby high-speed image formation is possible by a small-sized, simpleapparatus.

Though preferred embodiments of the image forming method and platemakingmethod in accordance with the present invention is explained in detailin the foregoing, the methods of the present invention should not berestricted to the above-mentioned embodiments.

For example, though one kind of self-assembling compound is used in theabove-mentioned embodiment, a mixture of at least two kinds ofself-assembling compounds may be used as well. In the following, anembodiment using two kinds of self-assembling compounds will beexplained with reference to FIGS. 1 and 5A to 5F.

Namely, first in this embodiment, a surface of a substrate 1 is immersedin a mixed solution 3 of two kinds of self-assembling compounds 2 (2 ₁,2 ₂) having main chain lengths different from each other, so as tosupply these self-assembling compounds 2 (2 ₁, 2 ₂) to the surface ofthe substrate 1. Consequently, as shown in FIG. 5A, two kinds ofself-assembling compounds 2 (2 ₁, 2 ₂) are mixed together and aresubstantially uniformly arranged at and adsorbed to the surface(solid-liquid interface) of the substrate 1 in a spontaneous manner, soas to form an adsorption film of a monomolecular film (self-assemblingmonomolecular film), thereby yielding an image forming body 4 (firstfilm forming step S101). Here, each of the two kinds of self-assemblingcompounds 2 (2 ₁, 2 ₂) is constituted by an adsorptive functional group2 a ₁, 2 a ₂, and an aliphatic compound residue 2 b ₁, 2 b ₂ combined tothe adsorptive functional group. As shown in FIG. 5B, the adsorptivefunctional group 2 a ₁, 2 a ₂ is adsorbed to the surface of thesubstrate 1, whereas the terminal of the aliphatic compound residue 2 b₁, 2 b ₂ is exposed to the surface of the self-assembling monomolecularfilm (the face on the exposed side). Then, as shown in FIG. 5B, a minuteuneven structure is formed on the surface of the self-assemblingmonomolecular film due to the difference in main chain length of thealiphatic compound residue 2 b ₁, 2 b ₂.

Subsequently, after the self-assembling monomolecular film is subjectedto the washing/drying processing (washing/drying step S102) as required,thermal energy 6 is selectively applied to the self-assembling compound2 (2 ₁, 2 ₂) from a thermal head 5, as shown in FIG. 5B, so as toselectively desorb the self-assembling compound 2 (2 ₁, 2 ₂) from thesurface of the image forming body 4 (first desorbing step S103).

In the desorption of the above-mentioned self-assembling compound 2 (2₁, 2 ₂), the self-assembling compound 2 (2 ₁, 2 ₂) to be desorbed is notneeded to be desorbed completely from the substrate 1. It will besufficient if, as shown in FIG. 6A, at least the aliphatic compoundresidue 2 b ₁, 2 b ₂ is desorbed (so as to leave the adsorptivefunctional group 2 a ₁, 2a₂ alone), whereby the wettability of thedesorbed face 7 and that of the undesorbed face 8 differ from eachother. Also, as shown in FIG. 6B, a part of the self-assembling compound2 (2 ₁, 2 ₂) on the desorbed face 7 may completely be desorbed, whileonly the aliphatic compound residue 2 b ₁, 2 b ₂ may be desorbed in theremaining self-assembling compound 2 (2 ₁, 2 ₂).

Subsequently, after moisture 10 from a moisture supply device 9 and ink(oil ink) 12 from a developing device 11 are successively supplied tothe surface of the image forming body 4 (moisture supply step S104 anddeveloping step S105) as shown in FIGS. 5C and 5D, the ink 12 istransferred to the recording medium 13 (transfer step S106) as shown inFIG. 5E.

Then, after the above-mentioned various steps (S104 to S107) arerepeated as indicated by A in FIG. 1 to complete the copy printing of adesired number of sheets (S108: “Yes”), thermal energy 15 from halogenlamps 14 is applied to the self-assembling compound 2 (2 ₁, 2 ₂) formingthe undesorbed face 8, as shown in FIG. 5F, so as to desorb theself-assembling compound 2 from the surface of the image forming body 4(second desorbing step S109). Thereafter, as indicated by B in FIG. 1,the self-assembling compound 2 (2 ₁, 2 ₂) is supplied to the surface ofthe image forming body 4 again, whereby the self-assemblingmonomolecular film is formed on the above-mentioned desorbed face again(second film forming step S101). Then, as the above-mentioned varioussteps (S101 to S109) are repeated, the copy printing of a desired numberof sheets is carried out for each of a plurality of images.

Here, since the self-assembling compound 2 (2 ₁, 2 ₂) tends to beadsorbed to the desorbed face 7 alone, as shown in FIG. 7, so as tore-form the monomolecular film in this part (see *9) in this embodimentas well, the second desorbing step S109 is not always necessary.

In this embodiment, since the minute uneven structure formed on thesurface of the self-assembling monomolecular film sufficiently preventsminute droplets from remaining on the surface, prints are prevented fromgetting soiled due to the remaining ink, and the prints are preventedfrom being whitened or the printing density from getting unstable due tothe remaining moisture, whereby a higher resolution tends to berealized.

Though a self-assembling monomolecular film is formed by means ofself-assembling compounds having main chain lengths different from eachother in the above-mentioned embodiment, self-assembling compounds 2 (2₁, 2 ₃) having steric configurations different from each other may beused, as shown in FIG. 8, to form a self-assembling monomolecular film4. Also in this case, two kinds of self-assembling compounds 2 (2 ₁, 2₃) are mixed together on the surface (solid-liquid interface) of thesubstrate 1 and substantially uniformly arranged and desorbed in aspontaneous manner, so as to form an adsorptive film of a monomolecularlayer (self-assembling monomolecular film), thereby yielding an imageforming body 4. Then, on the surface of the self-assemblingmonomolecular film, as shown in FIG. 8, a minute uneven structure isformed due to the difference in steric configuration of the aliphaticcompound residues 2 b ₁, 2 b ₃.

Also, though two kinds of self-assembling compounds are used for forminga self-assembling monomolecular film in the above-mentioned embodiment,three or more kinds may be used for forming a self-assemblingmonomolecular film.

Further, the above-mentioned embodiment indicates, as a method offorming the self-assembling monomolecular film, a method in which thesubstrate is immersed in a solution. As such a self-assemblingmonomolecular film forming method, however, a method in which thesolution is sprayed to the substrate as will be mentioned later, or amethod in which the solution is supplied to the substrate by way of aroller or blade may be employed as well.

Also, the above-mentioned embodiment indicates, as a method of desorbingthe self-assembling compound, a method based on heating utilizing athermal head, and a method based on heating by light irradiationutilizing halogen lamps. However, as such a desorbing method, a methodspraying a solvent and a method (see *10: J. Huang et al., Langmuir, 10(1994), 626-628) utilizing a photodecomposition reaction uponirradiation of light (e.g., ultraviolet rays) may be employed, withoutbeing restricted to the above-mentioned heating method.

The above-mentioned embodiment indicates a case where the desorbed faceis hydrophilic and lipophilic, whereas the undesorbed face iswater-repellent and lipophilic, in which oil ink is used. However, waterink may be used. In this case, since the water ink preferentiallyadheres to the desorbed face 7, the moisture supply step S104 becomesunnecessary. Also, the desorbed face may be hydrophilic and lipophilicwhereas the undesorbed face is water- and oil-repellent. In this case,since the oil ink preferentially adheres to the desorbed face 7, themoisture supply step S104 similarly becomes unnecessary.

In the following, preferred embodiments of the image forming apparatusin accordance with the present invention will be explained in detailwith reference to FIGS. 9 to 25. Among the drawings, parts identical orequivalent to each other will be referred to with numerals or lettersidentical to each other.

Embodiment 1

FIG. 9 is a schematic view showing a preferred embodiment of the imageforming apparatus in accordance with the present invention. A drum 1 bwhose surface has a gold film 1 a deposited thereon is used as an imageforming substrate 1. The above-mentioned drum 1 b is axially supportedso as to be rotatable, and is driven to rotate in the direction of arrowC. The configuration of the image forming apparatus (printer) will beexplained successively along the rotationally advancing direction of thedrum 1 b.

Installed under the drum 1 b is a film forming device (first filmforming device) 20 for forming a self-assembling monomolecular film madeof a self-assembling compound 2 onto the surface of the gold film 1 a.The film forming device 20 is constituted by a solution cartridge 20 afilled with a solution 3 of the self-assembling compound 2 and asolution sprayer 20 b. Filled in the solution cartridge 20 a is ann-hexane solution in which fluorodecanethiol-2 expressed by thefollowing formula:

C₈F₁₇(CH₂)₂SH

has been dissolved. Installed downstream thereof is a fan 20 c fordrying the surface of the gold film la supplied with the n-hexanesolution from the film forming device 20.

Subsequently installed is a first thermal head (first desorbing device)5 for selectively heating the surface of the image forming body 4 formedwith the self-assembling monomolecular film made of fluorodecanethiol-2,so as to form a printing plate.

Further installed is a developer (developing device) 11 for forming anink image on the image forming body 4. The developer 11 is constitutedby an ink feeder 11 a, an ink cartridge 11 b, ink (oil ink) 11 c, an inkfeeding roller 11 d, and an ink applying roller 11 e.

Installed above the drum 1 b is a transfer device 21 for transferringthe ink image formed onto the image forming body 4 by the developer 11to a recording medium 13. The transfer device 21 is constituted by apaper-feed roller 21 a and a platen roller 21 b.

Further installed is an ink cleaner 22 for eliminating the untransferredink on the drum 1 b. The ink cleaner 22 is constituted by a cleaningbuff 22 a and a take-up shaft 22 b.

Finally installed is a second thermal head (second desorbing device) 14for heating the whole surface of the image forming body 4 so as todesorb the self-assembling compound 2. Here, the above-mentioned firstfilm forming device 20 also acts as a second film forming device forre-forming a self-assembling monomolecular film onto the image formingbody 4 from which the self-assembling compound 2 has been eliminatedfrom the whole surface thereof by the second thermal head 14.

Operations in the above-mentioned apparatus will now be explained.

First, the second thermal head 14 is used for heating the whole surfaceof the gold film 1 a, thereby eliminating the impurities on the surfaceof the gold film 1 a. As a consequence, a denser self-assemblingmonomolecular film can be formed.

Next, the n-hexane solution in which fluorodecanethiol-2 has beendissolved is uniformly applied to the surface of the gold film la by thesolution sprayer 20 b of the film forming device 20. Then, the surfaceof the gold film 1 a coated with the above-mentioned n-hexane solutionis dried by the fan 20 c. A self-assembling monomolecular film made offluorodecanethiol-2 is uniformly formed on the dried gold film 1 a asshown in FIG. 10.

Subsequently, the first thermal head 5 is caused to act on the surfaceof the gold film 1 a uniformly formed with the self-assemblingmonomolecular film 2, so as to selectively heat the self-assemblingmonomolecular film 2, whereby fluorodecene is selectively desorbed asshown in FIG. 11.

Thus, the surface (desorbed face) of the gold film 1 a from whichfluorodecene has thus been desorbed becomes a surface combined with —SH.The surface (undesorbed face) covered with the self-assemblingmonomolecular film 2 is water- and oil-repellent, whereas the surface(desorbed face) in which —SH is combined to the gold film 1 a ishydrophilic and lipophilic. Thus, the surface of the image forming body4 would partly have different wettabilities. As a consequence, theselective heating by the first thermal head 5 can form any printingplate on the surface of the image forming body 4.

Subsequently, as the oil ink 11 c is supplied to the surface of theimage forming body 4 formed with the printing plate when the printingplate passes through the developer 11, an ink image is formed. Since thesurface (undesorbed face: non-image area) covered with theself-assembling monomolecular film 2 is oil-repellent, the oil ink 11 cwould not adhere thereto and only adheres to the desorbed face (imagearea) which is lipophilic. Here, while the film thickness of the ink 11c is adjusted by the surface roughness of the ink feeding roller 11 dand ink applying roller 11 e and by the pressure between the imageforming body 4 and the ink feeding roller 11 d and ink applying roller11 e, the oil ink 11 c is supplied onto the image forming body 4.

The recording medium 13 is fed by the paper-feed roller 21 a, along thedirection of arrow D, in synchronization with the rotation of the imageforming body 4. The recording medium 13 is pressed against the imageforming body 4 by the platen roller 21 b, and the ink image istransferred from the image forming body 4 to the recording medium 13while the recording medium is being pressed against the image formingbody 4. Thereafter, the recording medium 13 having the ink imagetransferred thereto is ejected along the direction of arrow D (nopaper-ejecting mechanism being depicted).

Untransferred ink may remain on the surface of the image forming body 4that has completed the above-mentioned printing step. The remaininguntransferred ink is scraped off by the ink cleaner 22. The cleaningbuff 22 a having scraped off the untransferred ink is taken up by thetake-up shaft 22 b. Here, the scraping of untransferred ink need notnecessarily be carried out per sheet but can be effected after aspecific number of sheets are printed (e.g., per 5 or 10 sheets) at thecopy printing using the same printing plate. The ink cleaner 22 isspaced from the image forming body 4 when not used for scraping off theuntransferred ink.

When a plurality of sheets are copy-printed for the same image, it isnot necessary for the film forming step and printing plate forming stepto be re-executed. Hence, the image forming body 4 is fed to thedeveloper 11 while holding the printing plate. During this period, thethermal heads 5, 14 are not heated. Also, it is preferred that, afterthe heating step or printing plate forming step is completed, thethermal heads 5, 14 be spaced from the image forming body 4 so that theself-assembling compound 2 is not desorbed by their residual heat. Inthe developer 11, the oil ink 11 c is supplied to the surface of theimage forming body 4, and the re-formed ink image is transferred to therecording medium 13.

After a desired number of sheets are copy-printed, the second thermalhead 14 approaches the drum 1 b, thereby heating the whole surface ofthe image forming body 4. Consequently, as with the reaction shown inFIG. 11, fluorodecene is desorbed from the whole surface of the goldfilm 1 a. Therefore, the surface of the gold film 1 a from whichfluorodecene has been desorbed becomes a surface combined with —SH.Subsequently, when printing a new printing pattern, the process isexecuted from the step of re-forming the self-assembling monomolecularfilm 2 onto the surface of the gold film 1 a. Namely, in the filmforming device 20, the n-hexane solution 3 containingfluorodecanethiol-2 dissolved therein is applied to the surface of thegold film 1 a by the solution sprayer 20 b, and the surface of the goldfilm 1 a is dried by the fan 20 c, whereby the surface of the gold film1 a can be re-modified with the self-assembling monomolecular film 2 asshown in FIG. 12. Then, with the subsequent steps similar to thosementioned above, the new printing pattern can be printed.

Embodiment 2

FIG. 13 is a schematic view showing another preferred embodiment of theimage forming apparatus in accordance with the present invention.Embodiments 1 and 2 differ from each other in the film forming devicefor forming the self-assembling monomolecular film onto the surface ofthe drum, the self-assembling compound and ink used, the transfer devicefor the image to the recording medium, and the device concerning thestep of re-forming the self-assembling monomolecular film.

Namely, a solvent bath 20 d for forming the self-assemblingmonomolecular film is installed under the drum 1 b. The solvent bath 20d stores an ethyl acetate solution in which decanethiol-2 expressed bythe following formula:

C₁₀H₂₁SH

has been dissolved. This solvent bath 20 d constitutes a film formingdevice (acting as both first and second film forming devices) 20.

The ink feeder (developing device) 11 is filled with water ink 11 c,whereas the configurations of the other devices (fan 20 c, first thermalhead 5, and developing device 11) concerning the printing plate formingstep (first desorbing step) and developing step are similar to those inEmbodiment 1. Also, the transfer device 21 in accordance with thisembodiment is constituted by a transfer drum 21 c, a paper-feed roller21 a, and a platen roller 21 b, whereas the transfer drum 21 c rotatesalong the direction of arrow E in synchronization with the rotation ofthe image forming body 4. In this embodiment, the transfer drum 21 c isalso provided with the ink cleaner 22. Further, no second thermal head14 is provided in this embodiment.

Operations in the above-mentioned apparatus will now be explained.

The drum 1 b having the gold film 1 a is rotated, while in a state wherethe lower end thereof is immersed in the solution 3 stored in thesolvent bath 20 d, along the direction of arrow C, whereby the ethylacetate solution containing decanethiol-2 dissolved therein is uniformlysupplied to the surface of the gold film 1 a. Then, the surface of thegold film 1 a supplied with the above-mentioned solution is dried by thefan 20 c. The self-assembling monomolecular film made of decanethiol-2is uniformly formed on the dried surface of the gold film 1 a as shownin FIG. 14.

Subsequently, the first thermal head 5 is caused to act on the surfaceof the gold film 1 a uniformly formed with the self-assemblingmonomolecular film 2, so as to selectively heat the self-assemblingmonomolecular film 2, whereby didecyldisulfide is selectively desorbedas shown in FIG. 15. Thus, decanethiolate is dimerized, anddidecyldisulfide is mainly evaporated.

Thus, the surface (desorbed face) of the gold film 1 a from whichdecanethiolate has been desorbed becomes a clean face. The surface(undesorbed face) covered with the self-assembling monomolecular film(decanethiolate) 2 is water-repellent and lipophilic, whereas the cleanface (desorbed face) to which the gold film 1 a is exposed ishydrophilic and lipophilic. Thus, the surface of the image forming body4 would partly have different wettabilities. As a consequence, theselective heating by the first thermal head 5 can form any printingplate on the surface of the image forming body 4.

Subsequently, as the water ink 11 c is supplied to the surface of theimage forming body 4 formed with the printing plate when the printingplate passes through the developer 11, an ink image is formed. Since thesurface (undesorbed face: non-image area) covered with theself-assembling monomolecular film 2 is water-repellent, the water ink11 c would not adhere thereto and only adheres to the desorbed face(image area) which is hydrophilic.

The recording medium 13 is fed by the paper-feed roller 21 a, along thedirection of arrow D, in synchronization with the rotation of thetransfer drum 21 c. The recording medium 13 is pressed against thetransfer drum 21 c by the platen roller 21 b. During the period when therecording medium 13 abuts against the transfer drum 21 c, the ink imageis transferred from the transfer drum 21 c to the recording medium 13.

After the above-mentioned transfer printing step is completed, theuntransferred ink remaining on the surfaces of image forming body 4 andtransfer drum 21 c is scraped off by the ink cleaner 22. When aplurality of sheets are copy-printed for the same image, as withEmbodiment 1, it is not necessary for the film forming step and printingplate forming step to be re-executed. Hence, the image forming body 4 isfed to the developer 11 while holding the printing plate, where the inkimage is formed again, and then to the transfer device 21, where the inkimage is transferred to the recording medium 13 again.

Then, after a desired number of sheets are copy-printed, aself-assembling monomolecular film for printing a new printing patternis formed again. Namely, the drum 1 b having the gold film 1 a isrotated, while in a state where the lower end thereof is immersed in thesolution 3 stored in the solvent bath 20 d, along the direction of arrowC, whereby the ethyl acetate solution containing decanethiol-2 dissolvedtherein is uniformly supplied to the surface of the gold film 1 a. Then,the surface of the gold film 1 a supplied with the above-mentionedsolution is dried by the fan 20 c. The self-assembling monomolecularfilm made of decanethiol-2 is uniformly formed again on the driedsurface of the gold film 1 a as shown in FIG. 16.

When printing a new printing pattern, the process is executed from thestep of causing the first thermal head 5 to selectively act on thesurface of the gold film 1 a re-formed with the self-assemblingmonomolecular film, so as to form a printing plate. Thus, it ispreferred that the self-assembling monomolecular film for the nextprinting process have been re-formed on the surface of the gold film 1 aat the time when the printing is completed. As a consequence, when thenext user starts printing, the step of forming the self-assemblingmonomolecular film can be omitted, whereby the printing time isshortened.

Since Embodiment 2 is configured such that the solvent bath 20 d is usedfor forming a film, the self-assembling compound 2 needed for formingthe self-assembling monomolecular film can be reduced. Also, thoughthere is a possibility of the image forming body 4, which is constitutedby the drum 1 b with the gold film 1 a deposited thereon, being damagedwhen the recording medium 13 directly comes into contact therewith, theimage forming body 4 would not be damaged or soiled by the recordingmedium 13 in this embodiment since the transfer drum 21 c is used forthe transfer to the recording medium 13. On the other hand, Embodiment 1has the advantage over Embodiment 2 in that the apparatus can be madesmaller as compared with Embodiment 2, since no transfer drum 21 c isused.

Embodiment 3

FIG. 17 is a schematic view showing another preferred embodiment of theimage forming apparatus in accordance with the present invention.Embodiments 1 and 3 differ from each other in the self-assemblingcompound used for forming the self-assembling monomolecular film, thedevice concerning the developing step, the transfer device for the imageonto the recording medium, and the device concerning the step ofre-forming the self-assembling monomolecular film.

Namely, installed under the drum 1 b is a film forming device 20 forforming a self-assembling monomolecular film, and a solution cartridge20 a is filled with an n-hexane solution in which a mixture ofdecanethiol 2 ₂ expressed by the following formula:

C₁₀H₂₁SH

and pentadecanethiol 2 ₂ expressed by the following formula:

C₁₅H₃₁SH

has been dissolved.

Also installed in this embodiment is a moisture supply device (dampeningdevice) 9 for supplying moisture to the desorbed face (non-image area)of the image forming body 4 formed with the printing plate with thefirst thermal head 5. Otherwise, the configurations of the devices (fan20 c, first thermal head 5, and developing device 11) concerning theprinting plate forming step (first desorbing step) and developing stepare similar to those in Embodiment 1. The moisture supply device 9 isconstituted by a moisture dispenser 9 a, a moisture cartridge 9 b,moisture (dampening solution) 9 c, a moisture supply roller 9 d, and amoisture applying roller 9 e. The transfer device 21 in accordance withthis embodiment is constituted by a transfer drum 21 c, a paper-feedroller 21 a, and a platen roller 21 bas with Embodiment 2. Further, inthis embodiment, a halogen lamp 14 is installed as the second desorbingdevice in place of the second thermal head.

Operations in the above-mentioned apparatus will now be explained.

First, the halogen lamp 14 is used for heating the whole surface of thegold film 1 a so as to eliminate impurities, and then the n-hexanesolution containing the mixture of decanethiol 2 ₂ and pentadecanethiol2 ₁ dissolved therein is supplied to the surface of the gold film 1 a bythe solution sprayer 20 b of the film forming device 20. Thereafter, thesurface of the gold film 1 a supplied with the above-mentioned n-hexanesolution is dried by the fan 20 c. As shown in FIG. 18, the driedsurface of the gold film 1 a is uniformly formed with a self-assemblingmonomolecular film 2 made of the mixture of decanethiol 2 ₂ andpentadecanethiol 2 ₁, and a minute (micro) uneven structure is formed onthe surface of the film.

Subsequently, the first thermal head 5 is caused to act on the surfaceof the gold film 1 a uniformly formed with the self-assemblingmonomolecular film 2, so as to selectively heat the self-assemblingmonomolecular film 2, whereby the self-assembling compound isselectively desorbed as shown in FIG. 19. The desorbed species aremainly constituted by decanethiol, pentadecanethiol, didecyldisulfide,dipentadecyldisulfide, and decylpentadecyldisulfide.

Thus, the surface (desorbed face) of the gold film 1 a from whichself-assembling compound has been desorbed becomes a clean face. Thesurface (undesorbed face) covered with the self-assembling monomolecularfilm 2 is water-repellent and lipophilic, whereas the clean face(desorbed face) is hydrophilic and lipophilic. Thus, the surface of theimage forming body 4 would partly have different wettabilities. As aconsequence, the selective heating by the first thermal head 5 can formany printing plate on the surface of the image forming body 4.

Subsequently, when the printing plate passes through the moisture supplydevice 9, the moisture 9 c is supplied to the desorbed face (non-imagearea) of the surface of the image forming body 4 formed with theprinting plate. Then, as the oil ink 11 c is supplied to the surface ofthe image forming body 4 formed with the printing plate when theprinting plate passes through the developer 11, an ink image is formed.Since the moisture 9 c is attached to the surface (desorbed face:non-image area), the oil ink 11 c would not adhere thereto and onlyadheres to the undesorbed face (image area) covered with theself-assembling monomolecular film 2. Subsequently, as with Embodiment2, the ink image is transferred to the recording medium 13 in thetransfer device 21.

After the above-mentioned transfer printing process is completed, theuntransferred ink is scraped off by the ink cleaner 22 as withEmbodiment 1. When a plurality of sheets are copy-printed for the sameimage, as with Embodiment 1, it is not necessary for the film formingstep and printing plate forming step to be re-executed. Hence, the imageforming body 4 is fed to the developer 11 while holding the printingplate, where the ink image is formed again, and then to the transferdevice 21, where the ink image is transferred to the recording medium 13again.

After the copy printing of a desired number of sheets is completed, thehalogen lamp 14 approaches the drum 1 b, so as to heat the whole surfaceof the image forming body 4. Consequently, as with the reaction shown inFIG. 19, the self-assembling compound 2 is desorbed from the wholesurface of the gold film 1 a. Hence, the surface of the gold film 1 afrom which the self-assembling compound 2 has been desorbed becomes aclean face. Subsequently, when printing a new printing pattern, theprocess is executed from the step of re-forming the self-assemblingmonomolecular film 2 onto the surface of the gold film 1 a. Namely, then-hexane solution 3 containing the mixture of decanethiol 22 andpentadecanethiol 21 dissolved therein is applied to the surface of thegold film 1 a by the film forming device 20, and the surface of the goldfilm 1 a is dried by the fan 20 c, whereby the surface of the gold film1 a can be re-modified with the self-assembling monomolecular film 2 asshown in FIG. 18. Then, with the subsequent steps similar to thosementioned above, the new printing pattern can be printed.

Embodiment 4

FIG. 20 is a schematic view showing another preferred embodiment of theimage forming apparatus in accordance with the present invention.Embodiments 3 and 4 differ from each other in the self-assemblingcompounds used for forming the self-assembling monomolecular film. Sincethe wettability of the self-assembling monomolecular film formed isoil-repellent, the moisture supply device 9, which has been necessary inEmbodiment 3, becomes unnecessary.

Namely, installed under the drum 1 b is a film forming device 20 forforming a self-assembling monomolecular film, and a solution cartridge20 a is filled with an n-hexane solution in which a mixture offluoropentadecanethiol 2, expressed by the following formula:

C₁₃F₂₇C₂H₄SH

and hydroxydodecylhydroxynonyldisulfide 2 ₂ expressed by the followingformula:

HOH₁₈C₉SSC₁₂H₂₄OH

have been dissolved. Here, though two kinds of self-assembling compoundsin Embodiment 3 are both water-repellent repellent and lipophilic, aself-assembling monomolecular film may be formed by a combination of awater- and oil-repellent self-assembling compound and a hydrophilic andoil-repellent self-assembling compound as shown in Embodiment 4.

The configurations of the devices (first thermal head 5, developingdevice 11, transfer device 21, ink cleaner 22, and halogen lamp 14)concerning the printing plate forming step (first desorbing step),developing step, transfer printing step, untransferred ink eliminatingstep, and second desorbing step are similar to those in Embodiment 3.

Operations in the above-mentioned apparatus will now be explained.

First, the halogen lamp 14 is used for heating the whole surface of thegold film 1 a so as to eliminate impurities, and then the n-hexanesolution containing the mixture of fluoropentadecanethiol 2 ₁ andhydroxydodecylhydroxynonyldisulfide 2 ₂ dissolved therein is supplied tothe surface of the gold film 1 a by the solution sprayer 20 b of thefilm forming device 20. Thereafter, the surface of the gold film 1 asupplied with the above-mentioned n-hexane solution is dried by the fan20 c. As shown in FIG. 21, the dried surface of the gold film 1 a isuniformly formed with a self-assembling monomolecular film 2 made of themixture of fluoropentadecanethiol 2 ₁ andhydroxydodecylhydroxynonyldisulfide 2 ₂, and a minute (micro) unevenstructure is formed on the surface of the film.

Subsequently, the first thermal head 5 is caused to act on the surfaceof the gold film 1 a uniformly formed with the self-assemblingmonomolecular film 2, so as to selectively heat the self-assemblingmonomolecular film 2, whereby at least a part of the self-assemblingcompound is selectively desorbed as shown in FIG. 22. The desorbedspecies are mainly constituted by fluoropentadecene andhydroxydodecylhydroxynonyldisulfide.

Thus, the surface (desorbed face) of the gold film 1 a from whichfluoropentadecene has been desorbed becomes a surface combined with —SH,whereas the surface (desorbed face) from whichhydroxydodecylhydroxynonyldisulfide has been desorbed becomes a cleanface. The surface combined with —SH and the clean face (desorbed face)both exhibit hydrophilic and lipophilic properties, whereas the surface(undesorbed face) covered with the self-assembling monomolecular film 2exhibits hydrophilic and oil-repellant properties. Thus, the surface ofthe image forming body 4 would partly have different wettabilities. As aconsequence, the selective heating by the first thermal head 5 can formany printing plate on the surface of the image forming body 4.

Subsequently, as oil ink 11 c is supplied to the surface of the imageforming body 4 formed with the printing plate when the printing platepasses through the developer 11, an ink image is formed. Since thesurface (undesorbed face: non-image area) covered with theself-assembling monomolecular film 2 is oil-repellent, the oil ink 11 cwould not adhere thereto and only adheres to the desorbed face (imagearea). Subsequently, as with Embodiment 3, the ink image is transferredto the recording medium 13 in the transfer device 21.

After the above-mentioned transfer printing process is completed, theuntransferred ink is scraped off by the ink cleaner 22 as withEmbodiment 3. When a plurality of sheets are copy-printed for the sameimage, as with Embodiment 3, it is not necessary for the film formingstep and printing plate forming step to be re-executed. Hence, the imageforming body 4 is fed to the developer 11 while holding the printingplate, where the ink image is formed again, and then to the transferdevice 21, where the ink image is transferred to the recording medium 13again.

After the copy printing of a desired number of sheets is completed, thehalogen lamp 14 heats the whole surface of the image forming body 4 aswith Embodiment 3. Consequently, as shown in FIG. 23, theself-assembling compound 2 is desorbed from the whole surface of thegold film 1 a. Here, the surface of the gold film 1 a heated as a wholebecomes a surface partly combined with —SH. Subsequently, when printinga new printing pattern, the process is executed from the step ofre-forming the self-assembling monomolecular film 2 onto the surface ofthe gold film 1 a. Namely, the n-hexane solution 3 containing themixture of fluoropentadecanethiol 2 ₁ andhydroxydodecylhydroxynonyldisulfide 2 ₂ dissolved therein is supplied tothe surface of the gold film 1 a by the film forming device 20, and thesurface of the gold film 1 a is dried by the fan 20 c, whereby thesurface of the gold film 1 a can be re-modified with the self-assemblingmonomolecular film 2 as with the reaction shown in FIG. 21. Then, withthe subsequent steps similar to those mentioned above, the new printingpattern can be printed.

Embodiment 5

Embodiments 3 and 4 differ from Embodiment 5 in the self-assemblingcompounds used for forming the self-assembling monomolecular film. Sincethe wettability of the self-assembling monomolecular film formed iswater- and oil-repellent, the moisture supply device 9, which has beennecessary in Embodiment 3, becomes unnecessary, and the image formingapparatus shown in FIG. 20 is employed.

Namely, installed under the drum 1 b is a film forming device 20 forforming a self-assembling monomolecular film, and a solution cartridge20 a is filled with an n-hexane solution in which a mixture of2,2-difluoromethylfluoropentadecanethiol 2 ₃ expressed by the followingformula:

(CF₃)₃CC₁₁F₂₂C₂H₄SH

and fluorodecanethiol 2 ₁ expressed by the following formula:

C₁₀F₂₁SH

has been dissolved.

The configurations of the devices (first thermal head 5, developingdevice 11, transfer device 21, ink cleaner 22, and halogen lamp 14)concerning the printing plate forming step (first desorbing step),developing step, transfer printing step, untransferred ink eliminatingstep, and second desorbing step are similar to those in Embodiment 3. Inthis embodiment, however, not only oil ink but also water ink can beused as ink 11 c.

Operations in the above-mentioned apparatus will now be explained.

First, the halogen lamp 14 is used for heating the whole surface of thegold film 1 a so as to eliminate impurities, and then the n-hexanesolution containing the mixture of2,2-difluoromethylfluoropentadecanethiol 2 ₃ and fluorodecanethiol 2 ₁dissolved therein is supplied to the surface of the gold film 1 a by thesolution sprayer 20 b of the film forming device 20. Thereafter, thesurface of the gold film 1 a supplied with the above-mentioned n-hexanesolution is dried by the fan 20 c. As shown in FIG. 24, the driedsurface of the gold film 1 a is uniformly formed with a self-assemblingmonomolecular film 2 made of the mixture of2,2-difluoromethylfluoropentadecanethiol 2 ₃ and fluorodecanethiol 2 ₁,and a minute (molecular-level) uneven structure is formed on the surfaceof the film.

Subsequently, the first thermal head 5 is caused to act on the surfaceof the gold film 1 a uniformly formed with the self-assemblingmonomolecular film 2, so as to selectively heat the self-assemblingmonomolecular film 2, whereby at least a part of the self-assemblingcompound is selectively desorbed as shown in FIG. 25. The desorbedspecies are mainly constituted by 2,2-difluoromethylfluoropentadeceneand fluorodecene.

Thus, the surface (desorbed face) of the gold film 1 a from which theself-assembling compound has been desorbed becomes a surface combinedwith —SH. The surface combined with —SH exhibits hydrophilic andlipophilic properties, whereas the surface (undesorbed face) coveredwith the self-assembling monomolecular film 2 exhibits water- andoil-repellent properties. Thus, the surface of the image forming body 4would partly have different wettabilities. As a consequence, theselective heating by the first thermal head 5 can form any printingplate on the surface of the image forming body 4.

Subsequently, as the oil or water ink 11 c is supplied to the surface ofthe image forming body 4 formed with the printing plate when theprinting plate passes through the developer 11, an ink image is formed.Since the surface (undesorbed face: non-image area) covered with theself-assembling monomolecular film 2 is water- and oil-repellent, theink 11 c would not adhere thereto and only adheres to the desorbed face(image area). Subsequently, as with Embodiment 3, the ink image istransferred to the recording medium 13 in the transfer device 21.

After the above-mentioned transfer printing process is completed, theuntransferred ink is scraped off by the ink cleaner 22 as withEmbodiment 3. When a plurality of sheets are copy-printed for the sameimage, as with Embodiment 1, it is not necessary for the film formingstep and printing plate forming step to be re-executed. Hence, the imageforming body 4 is fed to the developer 11 while holding the printingplate, where the ink image is formed again, and then to the transferdevice 21, where the ink image is transferred to the recording medium 13again.

After the copy printing of a desired number of sheets is completed, theuntransferred ink is eliminated by the ink cleaner 22. Subsequently,when printing a new printing pattern, the process is executed from thestep of re-forming the self-assembling monomolecular film 2 onto thesurface of the gold film 1 a. Namely, the n-hexane solution 3 containingthe mixture of 2,2-difluoromethylfluoropentadecanethiol 2 ₃ andfluorodecanethiol 2 ₁ dissolved therein is applied to the surface of thegold film 1 a by the film forming device 20, and the surface of the goldfilm 1 a is dried by the fan 20 c, whereby the surface of the gold film1 a can be re-modified with the self-assembling monomolecular film 2 aswith the reaction shown in FIG. 24. Then, with the subsequent stepssimilar to those mentioned above, the new printing pattern can beprinted. Though the self-assembling compound is desorbed by a halogenlamp (second desorbing device) in Embodiments 3 and 4 after the copyprinting of a desired number of sheets is completed, the desorbing stepby the second desorbing device may be omitted as shown in thisembodiment since the self-assembling compound tends to be selectivelyadsorbed to the desorbed face and re-form the monomolecular film.

While preferred embodiments of the image forming apparatus in accordancewith the present invention are explained in detail in the foregoing, theapparatus of the present invention should not be restricted to theabove-mentioned embodiments.

For example, the above-mentioned embodiments employ, as the substrate 1for forming the self-assembling monomolecular film, the drum 1 b onwhich the gold film 1 a is deposited. However, as noted, the substrateand self-assembling compound employed in the present invention shouldnot be restricted to those mentioned above.

In the following, the present invention will be explained in more detailwith reference to Examples, which are not limitative of the presentinvention.

EXAMPLE 1

As the substrate of the image forming body used for a printing plate,one in which a gold film (film thickness: 100 nm) had been deposited onan SUS plate (5 mm×5 mm) in vacuum was used. After the gold film surfaceof the above-mentioned substrate was heated at 350° C. for 60 minutesand then washed, the contact angle of distilled water with respect toits surface was measured (droplet amount: 7 μl) with a contact anglemeter (type CA-A, manufactured by Kyowa Interface Science Co., Ltd.) andfound to be 9°.

Also, decanethiol (C₁₀H₂₁SH) was used as a self-assembling compound.Namely, 80 mM of decanethiol were dissolved in 20 ml of n-hexane,whereby a 4-mM decanethiol/n-hexane solution was obtained.

When the gold film surface of the above-mentioned substrate was immersedin the above-mentioned decanethiol/n-hexane solution at roomtemperature, the above-mentioned decanethiol was substantially uniformlyadsorbed to the gold film surface, whereby a self-assemblingmonomolecular film was formed. Then, the gold film surface formed withthe above-mentioned self-assembling monomolecular film was dried with awarm current of air from a fan.

The contact angle of distilled water with respect to the gold filmsurface thus formed with the self-assembling monomolecular film wasmeasured in a manner similar to that mentioned above and found to be83°.

The foregoing results confirmed that the wettability of the surface hadchanged from hydrophilic to water-repellent as the above-mentioneddecanethiol was adsorbed to the gold film surface so as to form theself-assembling monomolecular film.

EXAMPLE 2

As the substrate of the image forming body used for a printing plate, aplate barrel on which a gold film (film thickness: 100 nm) had beendeposited was used. Also, as the self-assembling compound,1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8-heptadecafluorodecanethiol(C₈F₁₇CH₂CH₂SH) was used.

After the gold film surface of the above-mentioned substrate was heatedat 250° C. by a thermal head and then washed, an n-hexane solution ofthe above-mentioned thiol (concentration: 3 mM; temperature: 50° C.) wassupplied to the gold film surface, whereby the above-mentioned thiol wassubstantially uniformly adsorbed to the gold film surface, and aself-assembling monomolecular film was formed. Then, the gold filmsurface formed with the above-mentioned self-assembling monomolecularfilm made of the above-mentioned thiol was dried with a warm current ofair from a fan.

Subsequently, the gold film surface formed with the self-assemblingmonomolecular film was partly (at the part to be printed) heated to 250°C. with a thermal head so as to correspond to desired image data,whereby the above-mentioned self-assembling monomolecular film wasdesorbed from the heated part. As a consequence, a surface (undesorbedface) modified with the self-assembling monomolecular film and anunmodified surface (desorbed face) are formed on the above-mentionedgold film surface, thus allowing the printing plate in accordance withthe present invention to be obtained.

Thereafter, oil ink for printing news paper was applied to the surfaceof the above-mentioned printing plate, whereby the ink was repelled bythe surface (undesorbed face) modified with the above-mentionedself-assembling monomolecular film, whereas the surface (desorbed face)from which the above-mentioned self-assembling monomolecular film hadbeen desorbed held the ink, thus enabling an ink image to be formed.

Then, a printing paper sheet (recording medium) was pressed against thesurface of the printing plate formed with the above-mentioned ink image,and then the printing paper sheet was peeled off from the printingplate, whereby the ink image was transferred to the printing papersheet, thus completing the printing.

EXAMPLE 3

As the self-assembling compound,2,2-di-trifluoromethyl-1,1,1,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13-pentaeicosafluoropentadecanethiol[(CF₃)₃CC₁₁F₂₂C₂H₄SH] and1,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8-heptadecafluorodecanethiol[C₈F₁₇C₂H₄SH] were used. These two kinds of thiols were mixed such thatthe molar ratio between fluoropentadecanethiol and fluorodecanethiolbecame 1:1, and thus obtained mixture was dissolved in n-hexane, so asto prepare an n-hexane solution whose total thiol concentration became 1mM.

The n-hexane solution was supplied to and dried on the gold film surfacein the same manner as that of Example 2 except for the use of theabove-mentioned n-hexane solution, whereby a self-assemblingmonomolecular film, made of the above-mentioned two kinds of thiol,having a molecular-level minute uneven structure on the surface thereofwas formed on the gold film surface.

Subsequently, the gold film surface formed with the above-mentionedself-assembling monomolecular film was partly heated as with Example 2,whereby the above-mentioned gold film surface was formed with a surface(undesorbed face) modified with the self-assembling monomolecular filmand an unmodified surface (desorbed face) were formed, thus allowing aprinting plate in accordance with the present invention to be obtained.

Thereafter, ink was supplied to the surface of the above-mentionedprinting plate as with Example 2, whereby an ink image was formed aswith Example 2, thus making it possible to transfer the above-mentionedink image from printing plate to a printing paper sheet, so as tocomplete the printing.

Industrial Applicability

As explained in the foregoing, a so-called self-assembling monomolecularfilm was utilized as an image forming body in the image formingapparatus, image forming method, and platemaking method in accordancewith the present invention. As a consequence, desorbing at least a partof the self-assembling compound constituting the self-assemblingmonomolecular film can easily form and erase a printing plate withrespect to the image forming body.

Also, in the present invention, the same printing plate can be usedrepeatedly, whereby it becomes unnecessary to form a latent image persheet, which has been required in the conventional electrophotographicprinter, thus enabling high-speed printing.

Further, in the present invention, the same image forming body canrepeatedly be used for a plurality of images. Therefore, it does notnecessitate complicated devices and processes such as discarding astencil and winding a new stencil, which have been required in theconventional mimeograph printer. Hence, higher-speed image formation ismade possible with a small-size, simple apparatus, while realizing alower running cost at the time of copy-printing a small number of sheetswith the same original.

Also, since the image forming body in accordance with the presentinvention is formed by a self-assembling monomolecular film, individualbonds between molecules are controlled so as to form a plate. As aconsequence, in accordance with the present invention, edgecharacteristics of the plate become favorable, and an image printingplate having a higher resolution can be formed, wherebyhigher-resolution printing would be possible.

Further, since the bonding strength between the substrate surface andthe self-assembling monomolecular film is high, their bond would not besevered by the friction with respect to the recording medium or thelike. Therefore, the printing plate would not change during the printingin the apparatus and method of the present invention, wherebyhigh-quality printing is possible.

What is claimed is:
 1. An image forming apparatus comprising: an imageforming body comprising a substrate and a self-assembling compoundadsorbed to a surface of said substrate to form a self-assemblingmonomolecular film, said self-assembling compound having an adsorptivefunctional group adapted to be adsorbed to the surface of said substrateand an aliphatic compound residue, said self-assembling compound beingable to spontaneously form a substantially uniform adsorption film of amonomolecular layer on the surface of said substrate, wherein theadsorptive functional group is selected from the group consisting of: athiol (—SH), a disulfide (—SS—), a sulfide (—S—), an amine (—NH₂), adiazo (—N₂), an azide (—N₃), a silicon (Si), and an aldehyde (—COH); afirst desorbing device for selectively desorbing at least a part of saidself-assembling compound forming said self-assembling monomolecular filmfrom the surface of said image forming body, so as to provide thesurface of said image forming body with a desorbed face and anundesorbed face which have wettabilities different from each other; adeveloping device for supplying the surface of said image forming bodywith ink which preferentially attaches to one of said desorbed face orundesorbed face; and a transfer device for transferring to a recordingmedium the ink attached to the surface of said image forming body.
 2. Animage forming apparatus according to claim 1, wherein saidself-assembling compound is at least one compound selected from thegroup consisting of a thiol compound expressed by the following generalformula (1): HSR¹  (1) a disulfide compound expressed by the followinggeneral formula (2): R²SSR³  (2) and a sulfide compound expressed by thefollowing general formula (3): R⁴SR⁵  (3)
 3. An image forming apparatusaccording to claim 1, wherein said self-assembling compound is a mixtureof at least two kinds of self-assembling compounds which can be adsorbedto the surface of said substrate so as to form a self-assemblingmonomolecular film having a minute uneven structure.
 4. An image formingapparatus according to claim 3, wherein said at least two kinds ofself-assembling compounds have adsorptive functional groups adapted tobe adsorbed to the surface of said substrate and aliphatic compoundresidues combined to said adsorptive functional groups respectively,said aliphatic compound residues having main chain lengths differentfrom each other and exhibiting wettabilities identical to each other,said self-assembling compounds being able to spontaneously form on thesurface of said substrate an adsorption film of a monomolecular layerhaving a minute uneven structure.
 5. An image forming apparatusaccording to claim 3, wherein said at least two kinds of self-assemblingcompounds have adsorptive functional groups adapted to be adsorbed tothe surface of said substrate and aliphatic compound residues combinedto said adsorptive functional groups respectively, said aliphaticcompound residues having steric configurations different from each otherand exhibiting wettabilities identical to each other, saidself-assembling compounds being able to spontaneously form on thesurface of said substrate an adsorption film of a monomolecular layerhaving a minute uneven structure.
 6. An image forming apparatusaccording to claim 1, further comprising a first film forming device forsupplying said self-assembling compound to the surface of said substrateso as to form the self-assembling monomolecular film on the surface ofsaid substrate.
 7. An image forming apparatus according to claim 1,wherein the film forming device is configured to supply saidself-assembling compound to the surface of said image forming body so asto form the self-assembling monomolecular film on said desorbed faceagain.
 8. An image forming apparatus according to claim 7, furthercomprising a second desorbing device for desorbing the self-assemblingcompound forming said undesorbed face from the surface of said imageforming body so as to cause the whole surface of said image forming bodyto become the desorbed face.
 9. An image forming apparatus according toclaim 1, further comprising a moisture supply device which supplies,before said ink is supplied, moisture which preferentially attaches toone of said desorbed face or undesorbed face, to the surface of saidimage forming body.
 10. An image forming apparatus according to claim 1,wherein said desorbing device is a heating device which applies thermalenergy to the self-assembling compound forming said self-assemblingmonomolecular film, so as to desorb said compound.
 11. An image formingmethod including: a first desorbing step of selectively desorbing, froma surface of an image forming body comprising a substrate and aself-assembling compound adsorbed to a surface of said substrate to forma self-assembling film, at least a part of the self-assembling compoundforming said self-assembling monomolecular film, so as to provide thesurface of said image forming body with a desorbed face and anundesorbed face which have wettabilities different from each other, saidself-assembling compound having an adsorptive functional group adaptedto be adsorbed to the surface of said substrate and an aliphaticcompound residue, said self-assembling compound being able tospontaneously form a substantially uniform adsorption film of amonomolecular layer on the surface of said substrate, wherein theadsorptive functional group is selected from the group consisting of: athiol (—SH), a disulfide (—SS—), a sulfide (—S—), an amine (—NH₂), adiazo (—N₂), an azide (—N₃), a silicon (Si), and an aldehyde (—COH); adeveloping step of supplying the surface of said image forming body withink which preferentially attaches to one of said desorbed face orundesorbed face; and a transfer step of transferring a recording mediumthe ink attached to the surface of said image forming body.
 12. An imageforming method according to claim 11, wherein said self-assemblingcompound is at least one compound selected from the group consisting ofa thiol compound expressed by the following general formula (1):HSR¹  (1) a disulfide compound expressed by the following generalformula (2): R²SSR³  (2) a sulfide compound expressed by the followinggeneral and formula (3): R⁴SR⁵  (3)
 13. An image forming methodaccording to claim 11, wherein said self-assembling compound is amixture of at least two kinds of self-assembling compounds which can beadsorbed to the surface of said substrate so as to form aself-assembling monomolecular film having a minute uneven structure. 14.An image forming method according to claim 13, wherein said at least twokinds of self-assembling compounds have adsorptive functional groupsadapted to be adsorbed to the surface of said substrate and aliphaticcompound residues combined to said adsorptive functional groupsrespectively, said aliphatic compound residues having main chain lengthsdifferent from each other and exhibiting wettabilities identical to eachother, said self-assembling compounds being able to spontaneously formon the surface of said substrate an adsorption film of a monomolecularlayer having a minute uneven structure.
 15. An image forming methodaccording to claim 13, wherein said at least two kinds ofself-assembling compounds have adsorptive functional groups adapted tobe adsorbed to the surface of said substrate and aliphatic compoundresidues combined to said adsorptive functional groups respectively,said aliphatic compound residues having steric configurations differentfrom each other and exhibiting wettabilities identical to each other,said self-assembling compounds being able to spontaneously form on thesurface of said substrate an adsorption film of a monomolecular layerhaving a minute uneven structure.
 16. An image forming method accordingto claim 11, further comprising a first film forming step of supplyingsaid self-assembling compound to the surface of said substrate so as toform the self-assembling monomolecular film on the surface of saidsubstrate.
 17. An image forming method according to claim 11, furthercomprising a second film forming step of supplying said self-assemblingcompound to the surface of said image forming body so as to form theself-assembling monomolecular film on said desorbed face again.
 18. Animage forming method according to claim 17, further comprising a seconddesorbing step of desorbing the self-assembling compound forming saidundesorbed face from the surface of said image forming body so as tocause the whole surface of said image forming body to become thedesorbed face.
 19. An image forming method according to claim 11,further comprising a moisture supply step of supplying, before said inkis supplied, moisture which preferentially attaches to one of saiddesorbed face or undesorbed face, to the surface of said image formingbody.
 20. An image forming method according to claim 11, wherein saiddesorbing step is a heating step which applies thermal energy to theself-assembling compound forming said self-assembling monomolecularfilm, so as to desorb said compound.
 21. A platemaking method including:a desorbing step of selectively desorbing, from a surface of an imageforming body comprising a substrate and a self-assembling compoundadsorbed to a surface of said substrate to form a self-assembling film,at least a part of the self-assembling compound forming saidself-assembling monomolecular film so as to provide the surface of saidimage forming body with a desorbed face and an undesorbed face whichhave wettabilities different from each other, thereby yielding aprinting plate, said self-assembling compound having an adsorptivefunctional group adapted to be adsorbed to the surface of said substrateand an aliphatic compound residue, said self-assembling compound beingable to spontaneously form a substantially uniform adsorption film of amonomolecular layer on the surface of said substrate, wherein theadsorptive functional group is selected from the group consisting of: athiol (—SH), a disulfide (—SS—), a sulfide (—S—), an amine (—NH₂), adiazo (—N₂), an azide (—N₃), a silicon (Si), and an aldehyde (—COH). 22.A platemaking method according to claim 21, wherein said self-assemblingcompound is at least one compound selected from the group consisting ofa thiol compound expressed by the following general formula (1):HSR¹  (1) a disulfide compound expressed by the following generalformula (2): R²SSR³  (2) and a sulfide compound expressed by thefollowing general formula (3): R⁴SR⁵  (3)
 23. A platemaking methodaccording to claim 21, wherein said self-assembling compound is amixture of at least two kinds of self-assembling compounds which can beadsorbed to the surface of said substrate so as to form aself-assembling monomolecular film having a minute uneven structure. 24.A platemaking method according to claim 23, wherein said at least twokinds of self-assembling compounds have adsorptive functional groupsadapted to be adsorbed to the surface of said substrate and aliphaticcompound residues combined to said adsorptive functional groupsrespectively, said aliphatic compound residues having main chain lengthsdifferent from each other and exhibiting wettabilities identical to eachother, said self-assembling compounds being able to spontaneously formon the surface of said substrate an adsorption film of a monomolecularlayer having a minute uneven structure.
 25. A platemaking methodaccording to claim 23, wherein said at least two kinds ofself-assembling compounds have adsorptive functional groups adapted tobe adsorbed to the surface of said substrate and aliphatic compoundresidues combined to said adsorptive functional groups respectively,said aliphatic compound residues having steric configurations differentfrom each other and exhibiting wettabilities identical to each other,said self-assembling compounds being able to spontaneously form on thesurface of said substrate an adsorption film of a monomolecular layerhaving a minute uneven structure.
 26. A platemaking method according toclaim 21, further comprising a film forming step of supplying saidself-assembling compound to the surface of said substrate so as to formthe self-assembling monomolecular film on the surface of said substrate.27. A platemaking method according to claim 21, wherein said desorbingstep is a heating step which applies thermal energy to theself-assembling compound forming said self-assembling monomolecularfilm, so as to desorb said compound.